| The Spiral Model is the neo approach in IT project | | | | Planning Next Phase(III)--------------------Planning Next |
| system development and was originally devised by | | | | Phase(IV) |
| Barry W. Boehm through his article published in 1985 | | | | First Quadrant (I): the top left quadrant determines |
| "A Spiral Model of Software Development and | | | | and identifies the project objectives, alternatives, and |
| Enhancement". | | | | constrains of the project. Similar to the system |
| This model of development unites the features of | | | | conception stage in the Waterfall Model, here |
| the prototyping model with an iterative approach of | | | | objectives are determined with identifying possible |
| system development; combining elements of design | | | | obstacles and weighting alternative approaches. |
| and prototyping-in-stages. This model is an effort to | | | | Second Quadrant (II): the top right quadrant |
| combine the advantages of top-down and bottom-up | | | | determines the different alternatives of the project |
| concepts highly preferential for large, exclusive, | | | | risk analysis, and evaluates their task with each |
| volatile, and complex projects. | | | | alternative eventually resolving them. Probable |
| The term "spiral" is used to describe the process that | | | | alternatives are inspected and associated risks are |
| is followed in this model, as the development of the | | | | recognized. Resolutions of the project risks are |
| system takes place, the mechanisms go back several | | | | evaluated, and prototyping is used wherever |
| times over to earlier sequences, over and over again, | | | | necessary. |
| circulating like a spiral. | | | | Third Quadrant (III): the bottom right quadrant |
| The spiral model represents the evolutionary | | | | develops the system and this quadrant corresponds |
| approach of IT project system development and | | | | to the waterfall model with detailed requirements |
| carries the same activities over a number of cycles in | | | | determined for the project. |
| order to elucidate system requirements and its | | | | Fourth Quadrant (IV): the bottom left quadrant plans |
| solutions. | | | | the next phase development process, providing |
| Similar to the waterfall model, the spiral model has | | | | opportunity to analyze the results and feedback. |
| sequential cycles/stages, with each stage having to | | | | In each phase, it begins with a system design and |
| be completed before moving on to next. | | | | terminates with the client reviewing the progress |
| The prime difference between the waterfall model | | | | through prototyping. |
| and the spiral model is that the project system | | | | The major advantage of the spiral model over the |
| development cycle moves towards eventual | | | | waterfall model is the advance approach on setting |
| completion in both the models but in the spiral model | | | | project objectives, project risk management and |
| the cycles go back several times over to earlier | | | | project planning into the overall development cycle. |
| stages in a repetitive sequence. | | | | Additionally, another significant advantage is, the user |
| Progress Cycles, IT Project Management Solutions | | | | can be given some of the functionality before the |
| For Image: The Spiral Model | | | | entire system is completed. |
| The progress cycle of this model is divided into four | | | | The spiral model addresses complexity of |
| quadrants, and each quadrant with a different | | | | predetermined system performance by providing an |
| purpose; | | | | iterative approach to system development, repeating |
| Determining Objectives(I)-----------------Evaluating | | | | the same activities in order to clarify the problem and |
| Alternatives(II) | | | | provide an accurate classification of the requirement |
| ************** | | | | within the bounds of multiple constraints. |